With the advent of many different digital video systems, many types of interactive video have been developed. One type of interactive video is the inclusion of optional side trips. This type of interactive video allows users to follow a link out of the currently playing video to watch an alternate video sequence. At the end of the video sequence, or upon user input, the video presentation returns to the original video departure point and continues to play.
Expanding on the concept of optional side trips in video, detail on demand video comprises one or more base video sequences. Each base video sequence has one or more optional alternate video sequences. Each alternate video sequence provides additional details related to the base video sequence. During video playback, users may select the alternate video sequence to view this additional detail.
Upon user input or completion of the alternate video sequence, the presentation returns to the base video sequence. The location where the presentation resumes may be determined by the author. Additionally, alternate video sequences may have links to other video sequences, creating a hierarchical structure in which video sequences providing additional detail may in turn contain links for even more detail.
The nature of detail on demand video is well suited for creating training or “how-to” videos. In this application, viewers are able to get the level of explanation they need. The base video sequences may present an overview of the information at an abstract level. Users may follow a link from a base video sequence to view a more detailed presentation of the information in an alternate video sequence. Even further detail may be optionally provided by linking the alternate video sequence to another video sequence. This hierarchical presentation allows the viewer to watch detailed presentations of the topics in which they need the most help, while skipping over familiar portions of the presentation. This allows video guides to serve a wide audience by presenting a customized level of detail for each viewer. This also saves the viewer time by avoiding detailed presentations of information already familiar to the user.
Home video editing is another application for detail on demand video. Home users may create video summaries of family activities. More detailed presentations of different activities may be linked to the base video sequence to provide additional footage of interest. For example, a family video Christmas card may contain a main video sequence summarizing family activities for the year. Viewers may select a link during each portion of the main video sequence to view additional video from the family activity of interest. For examples, a grandparent may select additional video sequences of grandchildren, while other relatives may select addition details of a party or a family reunion.
It is desirable to offer a simple, yet flexible interface for creating detail on demand video. This interface should allow users to create detail on demand video without having to deal with the complexities associated with freeform hypervideo or nonlinear video editing. The interface should also support a hierarchical video structure. In order to facilitate rapid development, the interface should allow grouping of video clips into a video composite. The video composites may be used as building blocks to create video sequences or optional alternate video sequences. It is also desirable to specify the entry and exit points between a base video sequence and an alternate video sequence. This allows the alternate video sequence to function as a substitution for the base video sequence, rather than a side trip.
Given the limited real estate of the screen, it is desirable to have reduced representations of video composites. In order to be effective, the reduced representation should display important characteristics of its video sequence. These include the starting and ending clip since those are important to the author who must generate transitions between this sequence and other video being edited. Other useful information includes the other clips in the sequence, the time length of the sequence, the number of component clips, and the depth of the composite (for when the composite contains other composites.) It is further desirable to automatically select the most interesting area of a keyframe for incorporation in a video composite, or to visualize object motion over time.